Field of the Invention
The invention pertains to a monitoring process for a capacitor bushing with capacitor inserts condenser-Bushing in accordance with IEC137 or IEEE C57, and to a monitoring configuration performing the process.
A permanently monitored capacitor bushing configuration (also referred to as a capacitor lead-through) for large transtormers in three-phase systems has become known heretofore from German patent disclosure DE 36 01 934 A1. There, for each phase in a polyphase capacitor bushing, one tap between the capacitor inserts is provided, so that a reduced voltage can be picked up. The reduced voltages are then delivered to a bridge circuit, to which a measuring instrument is connected. In the event of an error, especially a short circuit between individual capacitor inserts, in one of the phases of the capacitor bushing, an error voltage is detected by the measuring instrument, and an error signal is generated. This kind of monitoring is suitable for detecting coarse errors within a polyphase capacitor bushing. Small errors, however, which might not at first impair operating performance, cannot be detected with that configuration.